1. Field of the Invention
Aspects of the present invention relate to techniques for a mobile communication. More particularly, aspects of the present invention relate to techniques for millimeter Wave (mmWave) mobile communication.
2. Description of the Related Art
Mobile communication has been one of the most successful innovations in the 20th century. In recent years, the number of subscribers to mobile communication services has exceeded 4.5 billion and is growing fast. At the same time, new mobile communication technologies have been developed to satisfy the increasing need for, and to provide more and better, mobile communication applications and services. Some examples of such systems are Code Division Multiple Access 2000 (CDMA2000) 1× EVolution-Data Optimized (EV-DO) systems developed by 3rd Generation Partnership Project 2 (3GPP2), Wideband Code Division Multiple Access (WCDMA), High Speed Packet Access (HSPA), and Long Term Evolution (LTE) systems developed by 3rd Generation Partnership Project (3GPP), and mobile Worldwide Interoperability for Microwave Access (WiMAX) systems developed by Institute of Electrical and Electronics Engineers (IEEE). As more and more people become users of mobile communication systems, and more and more services are provided over these systems, there is an increasing need for a mobile communication system with larger capacity, higher throughput, lower latency, and better reliability.
Millimeter Waves (mmWaves) are radio waves with wavelength in the range of 1 millimeter (mm)-10 mm, which corresponds to a radio frequency of 30 GigaHertz (GHz)-300 GHz. Per the definition by the International Telecommunications Union (ITU), these frequencies are also referred to as the Extremely High Frequency (EHF) band. These radio waves exhibit unique propagation characteristics. For example, compared with lower frequency radio waves, mmWaves suffer higher propagation loss, have a poorer ability to penetrate objects, such as buildings, walls, foliage, and are more susceptible to atmosphere absorption, deflection and diffraction due to particles (e.g., rain drops) in the air. On the other hand, due to the smaller wave lengths of the mmWaves, more antennas may be packed in a relatively small area, thereby allowing for the implementation of a high-gain antenna in small form factor. In addition, due to the aforementioned deemed disadvantages, mmWaves have been less utilized than the lower frequency radio waves. The limited utilization of mmWaves also presents unique opportunities for new businesses to acquire the spectrum in this band at a lower cost. The ITU defines frequencies in 3 GHz-30 GHz as Super High Frequency (SHF). Note that some higher frequencies in the SHF band also exhibit similar behavior as radio waves in the EHF band (i.e., mmWaves), such as large propagation loss and the possibility of implementing high-gain antennas in small form factors.
A vast amount of spectrum is available in the mmWave band. For example, the frequencies around 60 GHz, which are typically referred to as the 60 GHz band, are available as unlicensed spectrum in most countries. In the United States, 7 GHz of spectrum around 60 GHz (i.e., 57 GHz-64 GHz) is allocated for unlicensed use. On Oct. 16, 2003, the Federal Communications Commission (FCC) issued a Report and Order that allocated 12.9 GHz of spectrum for high-density fixed wireless services in the United States (i.e., 71-76 GHz, 81-86 GHz, and 92-95 GHz excluding 94.0-94.1 GHz for Federal Government use). The frequency allocation in 71-76 GHz, 81-86 GHz, and 92-95 GHz are collectively referred to as the E-band. The frequency allocation in the E-band is the largest spectrum allocation ever by the FCC as it is 50 times larger than the entire cellular spectrum.
MmWave wireless communication using component electronics has existed for many years. Several companies have developed or are developing mmWave communication systems that can achieve a Giga bits per second (Gbps) data rate. For example, Asyrmatos Incorporated developed an mmWave communication system capable of 10 Gbps data transfer over distances of several kilometers. The transceiver used by Asyrmatos Incorporated is based on photonics, which provides the flexibility of operating in a variety of mmWave bands such as the 140 GHz (F-Band), the 94 GHz (W-Band), the 70/80 GHz (E-Band), and the 35 GHz (Ka-Band). As another example, the GigaBeam Corporation developed multigigabit wireless technologies for the 70 GHz and 80 GHz band. However, these technologies are not suitable for commercial mobile communication due to issues such as cost, complexity, power consumption, and form factor. For example, GigaBeam Corporation's WiFiber G 1.25 Gbps wireless radio requires a two-foot antenna to achieve the antenna gain required for sufficient point-to-point link quality. The component electronics used in these systems, including power amplifiers, low noise amplifiers, mixers, oscillators, synthesizers, waveguides, are too big in size and consume too much power to be applicable in mobile communication.
Recently, many engineering and business efforts have been and are being invested to utilize the mmWaves for short-range wireless communication. A few companies and industrial consortiums have developed technologies and standards to transmit data at a G-bps rate using the unlicensed 60 GHz band within a few meters (i.e., up to 10 meters). Several industrial standards have been developed, e.g., WirelessHD technology, European Computer Manufacturers Association 387 (ECMA-387), and IEEE 802.15.3c, with other organizations also actively developing competing short-range 60 GHz G-bps connectivity technology, e.g., the Wireless Gigabit Alliance (WGA) and the IEEE 802.11 Task Group ad (TGad). Integrated Circuit (IC) based transceivers are also available for some of these technologies. For example, researchers at the Berkeley Wireless Research Center (BWRC) and the Georgia Electronics Design Center (GEDC) have made significant progresses in developing low-cost, low-power 60 GHz Radio Frequency IC (RFIC) and antenna solutions. Researchers from the BWRC have shown that 60 GHz power amplifiers may be designed and fabricated in 130 nanometer (nm) bulk “digital” Complementary Metal-Oxide-Semiconductor (CMOS). A core team of researchers from BWRC co-founded SiBeam Incorporated in 2004 and developed a CMOS based RFIC and baseband modem for WirelessHD technology. At present, the biggest challenge of short-range 60 GHz connectivity technology is the RFIC. As such, much of the engineering efforts have been invested to develop more power efficient 60 GHz RFICs. Many of the designs and technologies can be transferred to RFIC design for other mmWave bands, such as the 70-80-90 GHz band. Although the conventional 60 GHz RFICs still suffer from low efficiency and high cost, advancements in mmWave RFIC technology point to the direction of higher efficiency and lower cost, which may eventually enable communication over larger distance using mmWave RFICs.
Therefore, a need exists for techniques that utilize mmWaves for mobile communication.